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JOSH*, 35, COULD easily go weeks—or even months—without sex. That is, until he started Mounjaro two years ago. Within a few months he’d lost 11 pounds, while gaining the raging libido and erections of a teenager.

David*, 75, meanwhile, had the opposite experience. A few weeks after starting Wegovy, his sexual desire plummeted and he had difficulty reaching an orgasm.

These were temporary shifts that seemed to subside as the men continued on their GLP-1 medications. Still, their stories are raising important questions that researchers are trying to untangle as the meds boom in popularity.

In a 2025 Kinsey Institute survey , more than half of GLP-1 users reported that the medication had affected their sex lives—but the direction was divided: 16 percent said desire went down, while 18 percent said it went up, and 16 percent said sexual function improved while 12 percent said it worsened.…